Which two activities can be identified as common unscalable causes of suboptimal database performance?

Which two activities can be identified as common unscalable causes of suboptimal database
performance? (Choose two.)

A.
defining multiple buffer pools

B.
applications generating dynamic SQL

C.
large amounts of recursive SQL executed by SYS

D.
recursive SQL executed by a user other than SYS

E.
using cursors with bind variables that open the cursor and execute it many times